In the past ten years investigators at Ohio State University have used the powerful technique of X-ray crystallography for a wide variety of high-impact NIH-funded research, including the discovery of the 22nd genetically encoded amino acid in nature, structures of important RNA processing and DNA repair enzymes, proteins involved in bacterial quorum sensing, and regulation of nuclear hormone receptors. Multiple faculty members from three different colleges at Ohio State are using this technology for key aspects of their research programs. A shared facility housing state-of-the-art X-ray diffraction equipment has been up and running for the last four years. While in many ways Ohio State is thus poised for strength in this important research area, a major limitation is the absence of an automated system for crystallization. X-ray crystallography is an extremely powerful tool, but it requires that the sample molecule or complex of interest be crystallized, and in most cases, crystallization is the major bottleneck along the path to a successful structure determination. The aim of this proposal is to reduce the bottleneck in X-ray structure determinations at Ohio State through the acquisition of a Mosquito nano-volume automated pipetter. While the Mosquito instrument sets up crystallization experiments considerably faster and more accurately than with existing methodologies, the principle advantage is that the instrument uses 20-fold less sample per experiment. This allows the researcher to test 20-fold more crystallization cocktail solutions for a given amount of sample, which dramatically increases the chances of hitting upon suitable crystallization conditions. This can be a critical advantage when the amount of the sample of interest is in short supply, as is often the case. The Mosquito will allow researchers at Ohio State to set up approximately 20-fold more crystallization experiments, and thus enhance the chance for success in identifying optimal crystallization conditions. This in turn will greatly benefit a wide-range of NIH-funded projects of the major and minor users identified in this proposal as well as many other NIH-funded researchers at Ohio State who are engaged in crystallographic collaborations. HEALTH RELEVANCE: Crystal structures of proteins provide critical insight into the functions of proteins, and how they interact with small molecules. This information can be of great assistance in the design of novel drugs and pharmaceuticals. The crystallization robot requested in this proposal will help to grow crystals faster and thereby accelerate the ability of our NIH funded investigators to address issues of fundamental relevance to human health.